JPS5927770B2 - Synthetic paper with good ink adhesion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [I] BACKGROUND TECHNICAL FIELD OF THE INVENTION This invention relates to a synthetic paper having a layer containing an ethyleneimine adduct of a polyamine polyamide as an ink adhesion improver.

More specifically, this invention solves the problem of paper dust when coating an aqueous solution of polyamine polyamide-ethyleneimine additive on the paper-like layer surface of synthetic paper whose paper-like layer is a filled resin stretched film. Concerning synthetic paper manufactured without the hassle of In place of cellulose paper made of intertwined cellulose fibers, various synthetic papers made of synthetic resin films have been proposed.

As a group of such synthetic papers, there is one whose paper-like layer is a stretched resin film containing a filler. This group of synthetic papers includes single-layer structures consisting only of paper-like layers, as well as
There is a laminated structure in which such a paper-like layer is bonded to at least one side of a base material layer (see Japanese Patent Publication No. 40794/1983). The good paper-like properties of a synthetic paper whose paper-like layer is such a stretched resin film containing a filler are due to the presence of fine pores (boards) generated mainly from the filler.

These micropores are uniformly distributed throughout the thickness of the paper-like layer, but those on and near the surface communicate with the outside of the paper-like layer. The fact that the surface pores communicate with the outside and the filler is also exposed is based on the stretching of the filler-containing resin film, and this feature makes this group of synthetic papers essentially unique. It has good printability or ink receptivity (or ink absorption) and ink drying property. If such generally good printability were further improved, especially ink adhesion, the practicality of this group of synthetic papers would further improve.

Possible improvement measures A known method is to apply an aqueous polymer solution containing polyethyleneimine onto an oxidized polyolefin film and dry it to improve adhesion (Japanese Patent Publication No. 40-1).
(Refer to Publication No. 2302), it is reported that when a polyethyleneimine aqueous solution is applied to the paper-like layer surface of a synthetic paper whose paper-like layer is a filled resin stretched film and dried, the ink adhesion of this synthetic paper is improved. The inventors have discovered.

Location of the Problem However, the above-described characteristics of surface pores of synthetic paper whose paper dog layer is a stretched resin film containing a filler poses a problem when coated with an aqueous polyethyleneimine solution.

That is, this is a type of paper dust problem caused by the filler exposed on the surface peeling off from the surface of the paper layer.
In order to apply a polyethyleneimine aqueous solution to the paper-like layer in order to form a polyethyleneimine layer on the surface of the paper-like layer, the paper-like layer is brought into contact with a polyethyleneimine aqueous solution bath directly or indirectly via a transfer roll or the like. However, if the coating operation is continued for a long time, a white precipitate will form in the polyethyleneimine bath, making uniform coating difficult.

This white precipitate is the result of the filler exposed on the surface of the paper-like layer peeling off from the surface of the paper-like layer, entering the polyethyleneimine aqueous solution bath, and coagulating with the polyethyleneimine. Therefore, it is industrially difficult to coat a polyethyleneimine aqueous solution onto a paper-like layer of synthetic paper whose paper-like layer is a filled resin stretched film.

There may be polymer materials other than polyethyleneimine for improving ink adhesion that do not cause agglomeration of the release filler, but when selecting them, in addition to the effect of improving ink adhesion,
Care must also be taken not to unduly impair the paper properties and print-related properties of the treated synthetic paper.

By the way, the polyethyleneimine layer formed on synthetic paper shows good ink adhesion in the areas where printing ink is applied, but in other areas it impairs the feel of the synthetic paper and makes the surface sticky. There is a tendency to SUMMARY OF THE INVENTION The present invention aims to provide a solution to the above-mentioned points and achieves this object by using an ethyleneimine adduct of a polyamine polyamide as an ink adhesion improver formed on the surface of a paper-like layer. That is.

Therefore, the synthetic paper with good ink adhesion according to the present invention comprises a synthetic paper base material A having a paper-like layer made of a stretched resin film containing a filler, and an ink-adhesion improving layer B provided on the surface of the paper-like layer. The ink adhesion improving layer is mainly composed of an ethyleneimine adduct of polyamine polyamide.

In this way, in this invention, synthetic paper with a specific structure is coated with a specific polymer (this polymer is inherently water-soluble) on the paper-like layer. This product succeeded in solving a type of paper dust problem that is unique to synthetic paper.

That is, in this invention, a specific ethyleneimine additive is used as an ink adhesion improver, and this ethyleneimine additive exhibits good ink adhesion, and at the same time, its aqueous solution does not cause the release filler to aggregate. Can be coated for a long time. Furthermore, the synthetic paper provided with this ethyleneimine additive layer substantially retains its original paper feel and is not sticky. Furthermore, the synthetic paper coated with this ethyleneimine additive has extremely good adhesion with water-based adhesives or water-based inks, and it is possible to bond naturally with water-based adhesives or water-based inks, which was considered impossible with conventional synthetic paper because it has almost no water absorption. Paper adhesive or ink can be used.

Specific description of the invention 1. The paper-like layer is a stretched resin film containing a synthetic paper filler.

A group of synthetic papers of this type have a single-layer structure consisting of a filler-containing resin film stretched uniaxially or biaxially.

The other group has a laminated structure in which such a paper-like layer is bonded to at least one side of a base material layer.

A typical synthetic paper with such a laminated structure is one in which the paper-like layer is uniaxially stretched, the base layer is biaxially stretched, and the paper layer is stretched in the longitudinal direction (at least 1.3 times). ) It can be produced by extrusion laminating a filler-containing resin on at least one side of a resin film (which may contain a small amount of filler), and then laterally stretching (at least 2.5 times) this laminated body (especially (Refer to Publication No. 46-40794)
.

In either case, various stretchable thermoplastic resins (particularly those whose molecules are oriented by stretching) can be used alone or as a mixture as the synthetic resin for the film.

Specifically, for example, polyolefin resins such as homopolymers or copolymers of ethylene, propylene or butene-1, polyamide resins, polyester resins such as polyethylene terephthalate, polyvinyl or vinylidene resins such as vinyl chloride or vinylidene chloride homopolymers. Or copolymers, homopolymers or copolymers of styrene. In a laminated structure, the resin in each layer may be the same or different. Fillers are usually inorganic powders, specifically clay, clay, talc, asbestos, gypsum, barium sulfate, calcium carbonate, titanium oxide, zinc oxide, magnesium oxide,
There is diatomaceous earth, silicon oxide, and others. Particle size is 0.5
~30 microns is normal. The content may be sufficient as long as it exhibits sufficient paper-like properties, but the paper-like layer of the above-mentioned laminated structure should contain 5 to 60% by weight (especially 25 to 60% by weight).
The content is usually around 0% by weight. The printability of the surface of the paper-like layer can be further improved by oxidation treatment or other treatment.

2. Ethyleneimine Additive The ink adhesion improver used in the present invention is a water-soluble resin in which ethyleneimine is added to polyamine polyamide.

(1) Polyamine polyamide The polyamine polyamide to which ethyleneimine is to be added is obtained by a condensation reaction between a dicarboxylic acid and a polyalkylene polyamine.

(B) Dicarboxylic acid Aliphatic (including alicyclic) or aromatic saturated or unsaturated dibasic dicarboxylic acids having about 3 to 10 carbon atoms can be used alone or in mixtures, and the purpose of the present invention is to These may have a substituent unless contrary to the above.

Preferred dicarboxylic acids are saturated aliphatic dicarboxylic acids having 4 to 8 carbon atoms or phthalic acid, with adipic acid being particularly preferred from an economic standpoint.

(b) Polyalkylene polyamines Various types of polyalkylene polyamines in which the alkylene portion has about 2 to 4 carbon atoms, especially polyethylene polyamines, polypropylene polyamines,
Polybutylene polyamine, etc. are used.

The degree of polymerization (condensation) of "monomeric alkylene amine" is usually in the range of several tens to several tens of degrees.For economical reasons, polyethylene polyamine is suitable, specifically diethylene triamine, triethylene tetramine, etc. ,
Examples include tetraethylenepentamine.

H) Production of polyamide A polyamine polyamide can be produced by the reaction of a dicarboxylic acid and a polyalkylene polyamine by direct dehydration and amidation of both, dealcoholization using a dicarboxylic acid as an ester, or any other method for the purpose. All you have to do is implement it.

For example, in the case of a direct reaction between a dicarboxylic acid and a polyalkylene polyamine, the reaction temperature is about 110 to
It varies up to about 250℃, but usually about 160 to about 21℃.
The temperature is between 0℃ and 0℃.

The molar ratio of polyalkylene polyamine to dicarboxylic acid is
Usually the ratio is 0.8:1.0 to 1.4:1.0. 0.8
: A molar ratio of less than 1.0 tends to produce a gelled product or a product with a marked tendency to gel, while a molar ratio of 1.4:1
．． If the molar ratio exceeds 0, low molecular weight polyamide is likely to be produced.

Polyamine polyamides suitable for use in the present invention include:
Molecular weight (measured by osmotic pressure method) is 2000-10000
A value of about 0, preferably about 5,000 to 20,000 is suitable.

(2) Addition of ethyleneimine The addition of ethyleneimine to the polyamine polyamide as described above is generally promoted by an acid catalyst.

Examples of acids include inorganic acids such as sulfuric acid and hydrochloric acid, and organic acids such as acetic acid and butyric acid, which are used in a contact amount (for example, about 0.1 to 10% by weight relative to ethyleneimine). The addition reaction is generally carried out in solution, and the reaction temperature is room temperature to 100°C.
It is normal that it is about a certain degree. The ratio of polyamine polyamide to ethyleneimine is 9/1 to 1/9 in terms of polymerization ratio.
degree is preferred.

If this ratio exceeds 9/1, the ink adhesion will be unsatisfactory, and if it is less than 1/9, when an aqueous solution of the produced ethyleneimine adduct is used, there will be a strong tendency to agglomerate the release filler and it will take a long time to adhere to synthetic paper. coating work becomes impossible. The ethyleneimine adducts of polyamine polyamides obtained in this way are generally water-soluble.

Such polyamine polyamide-ethyleneimine adducts are well known and commercially available (for example, West German BA
[Polymin SN] manufactured by SF (solid content 30% by weight aqueous solution)
). 3. Coating bath is an aqueous solution containing the above copolymer.

The solvent usually consists of water only, but it may be a mixture with a water-soluble organic solvent (eg, alcohol, ketone) as long as a solution of the copolymer is produced. The aqueous solution of the copolymer may contain various auxiliary materials. One representative example of such an auxiliary material is a water-soluble polymer, particularly a surface-active polymer (ie, a polymeric surfactant). If a polymeric surfactant is used in combination, an antistatic effect can be imparted at the same time. The polymeric surfactant may be cationic, nonionic or amphoteric. Other examples of auxiliary materials that the aqueous solutions of the above copolymers may contain are inorganic salts, especially water-soluble inorganic salts, especially water-soluble inorganic salts of weak acids and strong alkalis.

By adding these water-soluble inorganic salts of weak acids and strong alkalis, the wetting of the polymeric surfactant to the synthetic paper becomes better, and the polymeric surfactant is uniformly applied to the surface of the synthetic paper. The antistatic effect increases. Such water-soluble inorganic salts also serve as an ink adhesion improving synergist. Specific examples of such inorganic salts include:
Sodium carbonate, sodium hydrogen carbonate, potassium carbonate,
There is sodium acetate. The above effects can also be expected by adjusting the pH of the aqueous solution to 8 to 10 by adding a small amount of a strong alkali, such as sodium hydroxide or potassium hydroxide. In addition, the copolymer aqueous solution may contain fillers, dyes and pigments, brighteners, antistatic agents other than those mentioned above, ultraviolet absorbers, ink drying agents, ink transfer agents, and others.

In particular, a small amount (approximately 0.01% to 1%) of fine fillers (0.1 to 10μ inorganic fillers, such as calcium carbonate, clay, diatomaceous earth, acid clay, titanium oxide, barium sulfate, talc, etc.) By adding it, it is possible to prevent a decrease in the slip properties of synthetic paper. The composition of the coating bath, expressed in weight percent as an aqueous solution, is generally as follows.

The synthetic paper targeted by this invention has sufficient adhesion to the polyamine polyamide-ethyleneimine adduct due to the unique structure of its paper-like layer. In order to improve the wettability to the aqueous solution and the adhesion to this copolymer, and to remove free or nearly peeled fillers, the surface of the paper-like layer can be subjected to a suitable pretreatment.

Appropriate pretreatments include electrical methods such as corona discharge treatment, thermal methods such as flame treatment, chemical methods such as acid treatment and dichromic acid treatment, and mechanical methods such as vacuum treatment. be.

Coating Polyamine Coating the aqueous solution of polyamide-ethyleneimine adduct can be carried out in any manner that can be employed in this type of technology.

For example, there are methods using a contact type air knife, size press, roll coater, etc., and non-contact type mist methods. The coating amount is arbitrary within the range that can achieve the desired effect, but is generally about 0.01-0.57/i based on the polyamine polyamide-ethyleneimine additive.

If it is less than 0.01y/Trl, the effect of improving ink adhesion will not be sufficient, while if it exceeds 0.57y/Trl, the good paper-like properties of the filler-containing resin stretched film paper-like layer will be impaired.
This is because ink drying properties, ink transfer properties, reverse trapping properties, blur removal properties, etc. tend to be poor.

After coating and drying, synthetic paper with excellent ink adhesion can be obtained.

5 experimental examples Hereinafter, the effects of this invention will be specifically illustrated by examples.

Example 1 A sheet made of a composition containing 8% clay with a particle size of 2μ, 3% diatomaceous earth with a particle size of 5μ, 89% polypropylene, and an antioxidant is prepared and stretched 5 times in the machine direction.

A composition consisting of 40% clay having a particle size of 2 μm and 60% polypropylene is extruded onto this longitudinally stretched sheet using an extruder and laminated on both sides of the longitudinally stretched sheet. By stretching this laminated sheet 7 times in the transverse direction, a synthetic paper having paper-like layers on both sides was obtained (Sample A). This synthetic paper
Corona discharge treatment was performed at an intensity of 50 W/M2·min.

This discharge treated synthetic paper (sample B) has a solid content of 0,
5% by weight of "Polymin SN", amphoteric polymer surfactant (
Patent Application No. 46-48248) 1.5% and Na2cO
3O. An aqueous solution containing 2% was applied and thoroughly dried (
Sample C). The resulting synthetic paper has the following properties:
The ink adhesion, cohesiveness during application, polyethylene laminate adhesion, etc. were as shown in the table, and were superior to other samples compared. The properties of comparative products, one using polyethyleneimine instead of the above-mentioned [Polymine SN] (sample D) and the other coated with only a polymeric surfactant (sample E), are shown in the table.

Example 2 The surface of the synthetic paper of Example 1 was subjected to a corona discharge treatment of 50 W/Trl·min, and 1.5% of a polymer surfactant was added to the surface of the synthetic paper of Example 1.
Na2cO3O. An aqueous solution containing 2% and the amounts of "Polymin SN" (same as in Example 1) shown in the table below was applied and dried.

The coating amount was 0.17/M2 in terms of solid content. The ink adhesion strength and water resistance of this synthetic paper were as follows, and those containing 0.1 to 2% of [Polymin SN] had excellent ink adhesion and water resistance.

Example 3 A laminated sheet was prepared in the same manner as in Example 1, and the laminated sheet was stretched under various conditions to obtain synthetic papers with different ink absorption properties.

These synthetic papers were corona discharged at 50 W/wl min and "Polymin SN" (same as Example 1) 0.5%
, polymeric surfactant 1.5%, Na2cO3O. Ink adhesion of an aqueous solution containing 2% and dried, [K
&N'' The ink absorption properties are as follows, and even in the case of samples with high ink absorption properties, the ink adhesion was improved upon coating.

Comparative example The synthetic paper of Example 1 was subjected to the following surface treatment.

The ink adhesion properties and the precipitates of the liquid after 10 hours of coating operation were as follows. Example 4 24% calcium carbonate with particle size 2μ, 66% polypropylene
, 4 in the longitudinal direction from a sheet made of 10% polyethylene
A board whitened synthetic paper was obtained by stretching the paper by 6 times in the transverse direction.

The ink adhesion of this synthetic paper was as follows. Example 5 Sample B obtained in Example 1 was added with a cationic surfactant (W.W represents CH3, R1/l represents C, 8H37).

) was coated with an aqueous solution containing 1.5% of Na2cO3 and 0.2% of Na2cO3 and thoroughly dried (sample L),
Adhesion tests were conducted on the above-mentioned Samples B and C, as well as a sample (Sample M) in which a 0.5% aqueous solution of "Polymin SN" was applied to Sample B, using a natural paper adhesive and a water-based ink. As is clear from this result, sample C and sample M according to the present invention have good adhesive properties.

Note that Sample B and Sample M have poor antistatic properties. Example 6 Samples 5 samples C1 and L prepared in the same manner as in Example 1 and Example 5 were affixed with a regular 1 yen stamp to natural paper, and were carried for 300 m using "Tensilon UTV 3" manufactured by Toyo Sokki Co., Ltd.
A tensile test was carried out at m/min to determine the peel strength of the stamps.

The results are as follows.

Sample C of the invention has extremely strong adhesion.

Example 7 Polymer surfactant 1.5 was added to the surface of sample B of Example 1.
%, Na2cO3O. Sample N1 Sample B coated with an aqueous solution containing 2% and 0.2% of kaolin clay with an average particle size of 1.2μ, "Polymin SN" (same as Example 1)
The blocking and slipping properties of Sample C were compared.

The results were as follows.

Sample C is a product of the present invention, and because the ink adhesion improver used contains an amphoteric polymeric surfactant and has water absorption properties, it exhibits less slipping and blocking than the control product (Sample B) under high humidity conditions. However, this problem has been solved with another product of the present invention (sample N).

As shown in Example 1, Sample C is superior to Sample B in ink adhesion, which is the essential objective of the present invention. Blocking test method Several tens of samples cut into 10x20CTrL were stacked and left under a pressure of 50k9/Cd for 30 minutes under test conditions of 25℃ and humidity, then the pressure was removed and the ease of peeling of each sheet was measured. judge.

Slip property test method: Stack several samples under the same conditions as the blocking test, apply pressure for 30 minutes, then take them out, press the samples from above and below with your hands, and slide them sideways.

Sample B had poor charging properties, and the slip was slightly reduced.

Example 8 (1) Preparation of ethyleneimine additive An ethyleneimine additive is prepared from a polyamine polyamide using triethylenetetramine instead of "Polymin SN", which is said to have diethylenetriamine as the polyalkylene polyamine component of the polyamine polyamide. Ivy.

3187 (2.18 moles) of triethylenetetramine and 1007 of water are placed in a three-necked flask with a stirrer, thermometer, and condenser.

Add 292y (2.0 mol) of adipic acid to this, and after dissolving it in the amine aqueous solution, the inside of the flask was
Heat to 130°C for minutes to remove water from the system. The temperature was gradually raised to 190°C as water was removed, and water 1347 was distilled off over about 6 hours, and the system was then cooled to 140°C. Water 3807 was then added to form a polyamine polyamide solution (solid 50%). This is called liquid B. B liquid 1
007 is placed in a five-loop flask equipped with a stirrer, a thermometer, a nitrogen inlet tube, a dropping load, and a condenser tube.

Add acetic acid to this to adjust the pH to 7. Additionally, 4.57 g of para-toluenesulfonic acid is added. After that, after purging the system with nitrogen, ethyleneimine 457 was added.
The mixture was heated to 5° C. and reacted for 1 hour, then ethyleneimine 1057 was added dropwise over 1 hour, the reaction was continued for another 3 hours, and then the temperature was raised and refluxed for 2 hours.

After the reaction was completed, the pH was adjusted to 5 with hydrochloric acid, and water was added to 25
% solids.

The polyamine polyamide/ethyleneimine weight ratio in the obtained ethyleneimine adduct was 1/3. The above aqueous solution was applied to Sample B described in Example 1 (coating amount was 0.17/m'' as solid content) to obtain synthetic paper with excellent ink adhesion.

Claims (1)

[Claims] 1 Consists of a synthetic paper base material having a paper-like layer made of a stretched resin film containing a filler, and an ink adhesion improving layer provided on the surface of the paper-like layer, and this ink adhesion improving layer is made of a polyamine polyamide with ethyleneimine added thereto. Synthetic paper with good ink adhesion, which is mainly composed of: